106 



EODENTIA 



ORDER VI 



Plesiospermophilus Filhol. Phosphorites of Quercy. 



Spermophilus Cuvier. Pouched marmots. Recent in the northern hemi- 

 sphere. Fossil in the Pleistocene. 



Frosciurus Matthew. White River Oligocene and John Day Miocene. 

 Transition between Paramys and Sciurus. 



Ardomys Gmelin. Marmot. Fossil in the European and North American 

 Pleistocene. 



Cynomys Rafinesque. North America. Fossil in the Upper Miocene and 

 onward. 



Sciurus Linn. Squirrel. Fossil in Europe and North America in the 

 Miocene and Pleistocene. 



Tamias Illiger. Recent and in the Pleistocene of North America. 



Sciuropterus Cuvier. Flying squirrels. Recent in Asia and in the north 

 part of Europe and North America. Upper Miocene of Germany. 



Pteromys Cuvier. Lophodont. Recent in Southern Asia. 



X. 3-2 

 1 3-2 



orbital foramen small 

 or less hypsodont. 



Family 3. Castoroidea. 



M. Cranial roof flat, mostly without postorhital process. Infra- 

 Cheek teeth with enamel folded into ridges and valleys, more 



Subfamily 1. Castorinae. Beavers. 



Skull low. f M. Cheek teeth more or less hypsodont. Upper teeth usually 

 with three outer and one inner fold, lower with three inner and one outer fold. 

 These folds are either transverse or parallel to the dental row. Tibia and fibula 

 fused distally. Recent in Europe and North America ; fossil forms ranging 

 from the Oligocene in the latter and from the Miocene in the former. 



Steneofiber Geoffroy (Chalicomys, Chelodus Kaup ; Palaeocastor Leidy) (Figs. 

 131, 132). Many species in the Miocene of North America, often in the 



Pig. 131. 



S(eneq/i6er /ossoj- Peterson. Upper Miocene, Sioux Co., Nebraska. Skeleton, s/g. (After Peterson.) 



Reproduced, hy permission, from 2 he Memoirs of the Carnegie Museum. 



European Miocene, less frequently in the Pliocene. The American forms 

 have a broad skull. The subterranean burrows are named Daemonelix. 

 Euhapsis Peterson. Lower Miocene ; North America. 



